Compound journal and thrust bearings are known from a number of prior publications. They have, in comparison with journal and thrust plain bearings made in one piece (flange bearings), the advantage that for the journal bearing part a different material may be used than for the thrust bearing part so that optimum adaptation of material to the specific loading conditions is possible.
To keep the wear of the bearing parts of a journal and thrust plain bearing as low as possible, the centering and fixing of the bearing parts with respect to each other is of great importance because a certain movability of the thrust bearing part relative to the journal bearing part is desired for the assembly of the plain bearing alone.
DE-OS 26 38 996 describes divided journal and thrust plain bearings in which the thrust bearing parts have noses functioning as retaining projections, which must be bent towards the bearing axis and engage into corresponding recesses made in the journal bearing part and open at the outer edge. Because the bent retaining projections should be supported on the bearing hole of the bearing housing, these retaining projections must be bent with high precision. The peripherally large extent of these retaining projections also requires an expensive bending process.
Finally the arrangement of the recesses does not offer the necessary safe fixing of the bearing parts in axial direction.
EP 298 953 describes a journal and thrust plain bearing composed of a bearing half-liner and a separate thrust flange in which, for the fixing of the flange on the bearing half-liner, the latter is provided with insertion openings which are open towards the outer edge and form a dovetail undercut acting in axial direction.
Corresponding to these insertion openings, fixing attachments are provided on the thrust flange which consist of tongues extending at an angle in axial direction. For this reason, even in the journal and thrust plain bearings known from EP 298 953, the retaining projections must be very long and be bent with high precision.
In order to connect the thrust flange with the bearing inlet, the thrust flange is seated on the bearing half-liner in radial direction. If all fixing attachments have a dovetail shape corresponding to the insertion openings, it is necessary to compress the bearing half-liner to insert the fixing attachments in the insertion openings. This compression eliminates not only the free speed of the bearing half-liner but also deforms the bearing half-liner in addition. This may damage the bearing half-liner.
If only the outer fixing attachments have a dovetail shape and may be inserted in the insertion recesses made for them by the use of the clearance desired between the journal bearing part and the thrust flange, a central fixing attachment must first be rectangularly made and after the seating of the thrust flange on the bearing half-liner widened in dovetail form. This widening in a dovetail form of the bent fixing attachments is difficult and there is a danger that the journal bearing part may be damaged.
In addition parts of a fixing attachment bent in a dovetail form have only a limited strength and retaining reliability and may be detrimental to the precision needed for the retaining projections of these known journal and thrust plain bearings.
DE-OS 33 45 652 and DE-OS 24 12 870 describe flanged half-bearings for use in engines. The connection between the semi-cylindrical bearing liner and the flange is performed by the hooking of radially extending stepped projections in the form of a convex prism in correspondingly profiled recesses of the journal bearing part which are open towards the outer edge but converge.
These recesses are situated on the arcuate edges of the liners. In this connection certain angular positions of the recesses and radially extending projections must be taken into consideration. It is disadvantage of this kind of connection that the manufacture is expensive because narrow tolerances must be achieved in the design and arrangement of the prisms and the recesses in addition to the angular positions. The prisms are furthermore stepped, embossed or milled. During assembly the journal bearing part must be deformed beyond normal measure. When, after the mounting of the flanged half-bearing, the free spread of the bearing liner is eliminated, the thrust bearing parts are no longer fixed and may even fall off the bearing liner.
GB-PS 22 10 113 describes a combined journal and thrust bearing in which the thrust bearing part has radially inwardly projecting fixing projections of rectangular shape and which engage in recesses of the journal bearing part which are undercut in axial direction. The manufacturing cost is, in this case, very high because undercut grooves must be made in the bearing liner.
A compound journal and thrust plain bearing is described in DE-PS 21 40 854 in which the thrust bearing part has radially inwardly extending slanted retaining projections which engage in corresponding axially recesses on the peripheral rim of the journal bearing part. In order to hold the thrust bearing part seated on the journal bearing part, small catches are provided on the recesses of the journal bearing part which should engage over the slanting of the retaining projections. Apart from the fact that such catches in the recesses of the journal bearing part require high precision and consequently high manufacturing costs, the attachment of the thrust bearing part to the journal bearing part is thereby not achieved with necessary reliability.
It is, therefore, an object of the invention to provide a compound journal and thrust plain bearing and also a method for its manufacture which ensures reliable fixing of the thrust bearing part on the journal bearing part and requires only a few working steps so that a cost-effective manufacture is achieved.